A common method for charging batteries is to charge with a constant current until the battery terminal voltage reaches the reference voltage and then continue charging while maintaining the battery terminal voltage at a constant voltage. As shown in prior art FIGS. 1 and 2, while charging with the constant voltage, the charging current decreases to a minimum value at which point the charging will be terminated. The decrease in the charging current is due to the internal battery impedance. As the internal battery voltage increases, the voltage across the internal battery impedance decreases due to the decrease in charging current until the current reaches a preset value, after which charging terminates. Therefore, charging in the constant voltage mode increases the charging time due to the lower charging current. Accordingly, a need exists for charging techniques which decrease battery recharging time.